If this is your first visit, be sure to
check out the FAQ by clicking the
link above. You may have to register
before you can post: click the register link above to proceed. To start viewing messages,
select the forum that you want to visit from the selection below.

Some Distributions Still Live In A KMS-Less World

03-25-2011, 12:10 PM

Phoronix: Some Distributions Still Live In A KMS-Less World

One of the most commonly mentioned terms at Phoronix is KMS, as in kernel mode-setting, whereby the GPU mode-setting is done in kernel-space rather than user-space with an X.Org DDX driver. The major open-source drivers were quick to adopt KMS support in their DRM drivers since it allows for cool features like a cleaner boot process, faster and more reliable VT switching, more reliable suspend-and-resume, greater security by running the X Server as a normal user, the ability to have a Linux kernel panic message (like a Windows BSOD), and for new technologies like the Wayland Display Server to emerge. However, not all Linux distributions are yet on this KMS bandwagon...

Comment

Yes, I use fglrx from time to time. Yes, it sadly doesn't work with any Kernel graphic parts. But then it brings my whole system to 85W idle. (Windows w. Catalyst is 90W and KMS is 95W at best).
So with KMS I still have 10W more on idle, there is a bunch of rendering problems here and there, somehow I lack the bootup and init screen completely after KMS kicks in and my monitor is without signal until X rises up. (Did not do so on an older kernel, now using 2.6.38). And then, just a few minutes ago I had to REISUB (!) just after switching a few tabs in the browser. System completely frozen. Grrr.

So without KMS my system runs better (or say: more stable and reliable) - a.t.m.. Still I hope for KMS to fully work soon on my RV670.
But I DO understand that KMS is still not ready for productive system in the very close future. Maybe <=R500 and most intel chips do already fine.

Stop TCPA, stupid software patents and corrupt politicians!

Comment

I prefer the non-KMS VT's. They don't rely on so much hardware acceleration and put less strain on the system. Sure they might be a bit slower but they work extremely reliable on almost all graphic cards/chips that you can run Linux on.
The same can not be said for hardware accelerated OpenGL and similar.

A few years ago I suffered from flaky hardware (in part due to a really bad power supply) for a couple of months and that made me really appreciate stability when it comes to system-critical tasks.

It's annoying when the display driver crashes, but at least you'll have a chance to kill and restart X. How do you kill and restart a KMS VT?

Comment

I prefer the non-KMS VT's. They don't rely on so much hardware acceleration and put less strain on the system. Sure they might be a bit slower but they work extremely reliable on almost all graphic cards/chips that you can run Linux on.
The same can not be said for hardware accelerated OpenGL and similar.

A few years ago I suffered from flaky hardware (in part due to a really bad power supply) for a couple of months and that made me really appreciate stability when it comes to system-critical tasks.

It's annoying when the display driver crashes, but at least you'll have a chance to kill and restart X. How do you kill and restart a KMS VT?